(a) Field of the Invention
The present invention relates to a mounting bolt for a sub-frame. More particularly, the present invention relates to a mounting bolt for a sub-frame that reduces cost and weight and maintains robustness thereof.
(b) Description of the Related Art
Generally, in a monocoque vehicle body, a sub-frame is assembled to a lower portion of a front side member to support a lower portion of an engine (not shown) and a transmission (not shown) and induces the engine and the transmission to drop when a front end of a vehicle crashes, and prevents the engine or the transmission from entering an inner space through a dash panel of a vehicle body to secure safety of a passenger.
FIG. 1 is a perspective view for describing a sub-frame that is assembled to a lower portion of a front side member for a conventional vehicle, and FIG. 2 is a perspective view showing a condition in which a mounting bolt for a sub-frame is applied according to a conventional art.
Referring to FIG. 1, both sides of a front and a rear of the sub-frame 101 are assembled by a mounting unit 100 for a frame (hereinafter, a mounting unit) that is configured at a lower portion of both sides of a front side member 103.
Referring to FIG. 2, the mounting unit 100 includes a mounting bolt 110 that is fixed to both sides of a front side and a rear side of the front side member 103 through a mounting bracket 105, and both sides of a front side and a rear side of the sub-frame 101 are assembled to the mounting bolt 110.
That is, the mounting bracket 105 is joined to a lower portion of both sides of a front and a rear of the front side member 103, and the mounting bolt 10 is joined by CO2 welding or projection welding in a condition in which it is inserted into a through-hole 107 formed on a mounting bracket 105.
Here, the mounting bolt 10 is integrally formed by cold forging or hot forging, and is welded in a condition in which it is supported by a circumference of the through-hole 107 of the mounting bracket 105 by a head portion 111 that is formed along one side circumference.
The mounting bolt 10 that is configured as described above is one of components of a vehicle, but there is a drawback that the weight is unnecessarily heavy, because it is integrally formed by cold forging or hot forging, which increases cost.
The Description of the Related Art is given to help understanding of the background of the present invention and may include matters out of the related art known to those skilled in the art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.